Herbaceous Flora of Blackland Prairie Remnants in Mississippi and Western Alabama

Castanea, Dec 2007 by Barone, John A, Hill, Jovonn G

Of Lowe's (1911, 1921) 19 species characteristic of Black Belt prairies, 14 were observed either in the current study or by Schuster and McDaniel (1973), Leidolf and McDaniel (1998), or Forbes (1999). The five species noted by Lowe (1921) but not observed on extant prairies were: Coreopsis grandiflora Hogg ex Sweet, Liatris graminifolia Willd., Oenothera triloba Nutt., Rudbeckia laciniata L., and Silene virginica L.

Mohr (1901) lists 28 native forbs and 12 native grasses of Black Belt prairies in Alabama. Of the forbs, three are apparently absent from prairie remnants: Helianthus hirsutus Raf., Myosotis verna Nutt. and Polygala mariana P. Mill. Seven of the grass species reported by Mohr (1901) were observed on relid prairies in this study or by Schuster and McDaniel (1973). The remaining five grass species that have not been recently seen are: Chasmanthium latifolium (Michx.) Yates, Eragrostis pectinacea (Michx) Nees ex Steud., Eragrostis refracta (Muhl.) Scribn., Paspalum laeve Michx. and Paspalum distichum L.

For the Jackson Prairie Belt, Lowe (1921) regards 17 forbs as charaderistic of the prairies. Five of these were not observed by Jones (1971), Moran et al. (2003) or in the present study: Delphinium carolinianum Walt., Linum virginianum L., Baptisia alba (L.) Vent., Silphium scaberrimum ElL, and Tephrosia spicata (Walter) Torr. & Gray.

Therefore, 18 spedes listed by Lowe (1911, 1921) and Mohr (1901) as part of the prairie flora are apparently rare or absent from remnant prairies. Of course, they may yet be found, but they clearly are no longer common, at least in western Alabama and in Mississippi. While their absence could be the consequence of a decrease in habitat area, an alternative explanation is that the species composition of existing prairie sites may not be representative of the historical prairies. This point, in fad, is made by Mohr (1901) who notes that even in the early 1900's prairies in the Alabama Black Belt with deep soils were cultivated and that "only the poorest spots remain in the original state." Agricultural development, urban growth and concomitant environmental changes since 1901 would have only exacerbated this situation. Prairies with deeper or, quite likely, sandier soils, or sites near waterways are the most likely to have been converted to farmland or pastures. These more mesic sites may also have included broader prairie-forest ecotones that are absent from extant remnants. Prairies with thinner, more clayey soils have survived through negled. Thus, we exped that plant species on extant prairies are those that are most tolerant of drier, harsher conditions, and that the missing species are most likely ones requiring more mesic or sandier, better-drained conditions.

To examine this conjecture, we reviewed the habitat preferences of the absent species, using descriptions from Jones (2005) and Radford et al. (1968) and herbarium specimens in the Pullen Herbarium (MISS) at the University of Mississippi (http://www.herbarium.olemiss. edu; accessed October 2 to 5, 2006; McCook and Kartesz 2000). For example, of the 20 specimens of Silene virginica in the Herbarium with habitat information, four were from sites near water, six were from sites with sandy soils and ten were colleded from wooded areas. None were colleded from prairies, though some of the oldest specimens, which lacked habitat information, were taken from sites that were near historic prairies.